1. Field of the Invention
The invention relates to a heat dissipation module and a flow direction controlling structure thereof, and particularly to a heat dissipation module with a flow direction controlling structure capable of controlling air flow and preventing outside air flow entering the heat dissipation module.
2. Brief Discussion of the Related Art
As efficiency of electronic devices increases rapidly, heat dissipation apparatuses have become essential elements thereof. Heat generated by the electronic devices, if not properly dissipated, can lead to decreased efficiency or even burnout of the electronic devices. Particularly, heat dissipation apparatuses are critical to micro-electrical elements, such as integrated circuits (ICs). As integration increases and package technology improves, size of the ICs is reduced, and heat accumulated in the unit area thereof increases. As a result, heat dissipation apparatuses with high efficiency are a major area of development.
Generally, ventilation, convection or heat dissipation in a heat generating system such as a server, a computer, an electronic mechanism or a power supply is facilitated by a heat dissipation apparatus, such as an axial flow fan, or a centrifugal fan. The heat dissipation apparatus can guide air flow to dissipate heat generated by the electronic devices to the environment for performing heat dissipation or air convection.
FIG. 1A illustrates a conventional parallel fan module. The conventional parallel fan module 10 includes a first blower 110 and a second blower 120 for discharging air inside the first blower 110 and the second blower 120 to be respectively vented through the outlet 111 and the outlet 121.
When the first blower 110 and the second blower 120 are in operation, the first blower 110 and the second blower 120 discharge the air through the outlet 111 and the outlet 121, respectively. However, the blowers 110 and/or 120 may has glitch or malfunction. When one of the blowers 110 and 120 malfunctions, for example, the second blower 120 malfunctions, only the first blower 110 is in operation, and the air inside the first blower 110 is still able to be discharged through the outlet 111. The outlet 121 of the second blower 120 is wide opens to the environment, which may lead to backflow and air accumulation in the second blower 120. In this case, the first blower 110 may be affected by the backflow to reduce heat dissipation efficiency of the entirety of the parallel fan module 10.
Conventionally, a compensation mechanism is provided to increase power of the blower in operation. With the compensation mechanism, power of the blower in operation is increased to compensate for the malfunctioning blower such that forced convection occurs in the second blower 120 to discharge the fluid accumulated in the first blower 110 and the second blower 120. The compensation mechanism, however, increases cost and complexity of the structure, and does not provide real-time compensation since reaction time is required to implement compensation from the time when one of the blowers is detected as malfunction. Further, backflow is not completely prevented since the outlet 121 remains open to the environment.
In another conventional solution, a plurality of flappers is provided at the outlets to prevent from the backflow. An example is shown in FIG. 1B, FIG. 1C and FIG. 1D. FIG. 1B illustrates a conventional parallel fan module with flappers, in which the blowers are not in operation. FIG. 1C illustrates the conventional parallel fan module with flappers in operation. FIG. 1D illustrates the conventional parallel fan module with flappers in which one of the blowers malfunctions. In the conventional parallel fan module 10, a flapper 112 is installed at the outlet 111 of the first blower 110, and a flapper 122 is installed at the outlet 121 of the second blower 120. When the first blower 110 and the second blower 120 are not in operation, the flappers 112 and 122 are in a closed position, as shown in FIG. 1B, by gravity or other specific design (such as a biased device) to seal the outlet 111 and the outlet 112.
When the first blower 110 and the second blower 120 are in operation, the air within the first blower 110 and the second blower 120 is respectively discharged through the outlet 111 and the outlet 121, generating a flow force to the flappers 112 and 122 such that the flappers 112 and 122 move to an open position as shown in FIG. 1C.
When one of the blowers, such as the second blower 120, malfunctions, only the first blower 110 is in operation as shown in FIG. 1D. In this case, the flapper 112 at the outlet 111 is moved to the open position by the flow force, but the flapper 122 at the outlet 121 maintains in the closed position since no flow force is generated in the second blower 120. Thus, the outlet 121 of the second blower 120 is sealed such that fluid in the environment does not backflow to the malfunctioning second blower 120, preventing hot air accumulation and reduction in heat dissipation efficiency.
The flappers, however, are respectively disposed at the blowers. When one blower in the heat dissipation module malfunctions, the outlet of the malfunctioned blower is sealed by the flapper thereof to prevent backflow. Thus, there is no heat dissipation to the heat source corresponding to the sealed outlet, which leads to heat accumulation at the heat source and reduction of heat dissipation efficiency. Further, the whole outlet area of the heat dissipation module is reduced. In the conventional parallel fan module in FIG. 1D, for example, the original whole outlet area, including the outlet 111 and the outlet 121, is reduced to be half one when the flapper 122 seals the outlet 121, which seriously deteriorates heat dissipation effect.